PS Magazine - TB 43-PS-569
PS, The Preventative Maintenance Monthly
ISSUE 569
APRIL 2000
M109A2-A5 SP Howitzers . . .
Keep the Ram in Your Rammer
C
rewmen, the formula is simple: Exert enough pressure for long enough and
anything will come loose.
That goes for the small screws that hold the track cover in place on your
M109A2-A5 howitzer’s rammer assembly.
The constant movement and vibration from ramming ammo eventually loos-
ens the screws. If some of the screws are missing or not tight enough, the cover
doesn’t make contact with the blocking valve.
When that happens, the blocking
valve doesn’t open all the way and
there’s not enough hydraulic fluid
available for the rammer to properly
seat the projectile.
Check the screws at least weekly to
make sure they’re not loose or miss-
ing. Replace missing screws with NSN
rewmen, depending on memory to do
your howitzer’s primary prefire checks
and services can be a problem, especially
since there have been a few changes
lately.
The index guide pins on the recuperator
must now extend
1
/
4
to
3
/
4
inch in order
for your vehicle to be FMC. Also, the
tube borescope maintenance interval has
been increased from 90 to 180 days.
To help jog your memory, a new decal
is available that lists all of the primary
prefire checks and services.
Place the new decal, NSN 9905-01-
037-0245, on the accumulator next to the
“CAUTION CLOSE BUSTLE DOORS
BEFORE TRAVERSING CAB” decal.
Recovery Vehicles . . .
M109-Series SP Howitzers . . .
The 11-ft long lifter is made of 1
1
/
2
-in diameter steel pipe that is
1
/
8
inch thick.
It has a 14-in long tee made from the same pipe that fits in the V-shaped end of
the tow bar.
After attaching the tow bar to the disabled vehicle, two people use the lifter to
hold the tow bar up. The recovery vehicle driver makes the hookup with the help
of the ground guides.
The lifter is designed to work with all Army tow bars and recovery vehicles,
including the 5-ton wrecker.
5
1
/
2
"
4
1
/
4
"
11'
Use 1
1
/
2
-in steel pipe to make lifter
14"
PRIMARY PREFIRE CHECKS AND SERVICES
1. TRAVEL LOCK : UNLOCKED AND STOWED.
2. RECOIL SYSTEM : BUFFER AND RECOIL SYSTEM
BLED, REPLENISHER GAGE PRESSURE WITHIN
OPERATING RANGE, RECUPERATOR INDEX PINS
PROTRUDE 1/4 INCH TO 3/4 INCH.
3. TUBE : UNOBSTRUCTED, BORESCOPED WITHIN
LAST 180 DAYS-IAW TM9-1000-202.
4. BREECHBLOCK : SMOOTH OPERATION, COMPLETE
CLOSING.
5. FIRING MECHANISM : PROPER FUNCTIONING,
FIRING PIN SERVICEABLE.
this
lifting
bar
sure makes
light work
out
of a
heavy
job
.
Check cover screws weekly
PS 569
19
APR 00
PS 569
18
APR 00
echanics, hooking up the tow bar when recovering a disabled combat
vehicle is one of the most difficult—and dangerous—jobs you have to do.
Not only is that tow bar back-breakingly heavy, but who wants to stand
between several tons of metal that might move suddenly?
The solution is a homemade tow bar lifter. It makes your job a lot easier and
safer. You won’t have to stand between vehicles to hook up the tow bar. And,
with two people lifting, the load is a lot lighter.
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